UML2.0 introduced interaction overview diagrams (IODs) as a way of specifying relationships between UML interactions. IODs are a variant of activity diagrams that show control flow between a set of interactions. The nodes in an IOD are either inline interactions or references to an interaction. A number of recent papers have defined a formal semantics for IODs. These are restricted, however, to interactions that can be specified using basic sequence diagrams. This excludes the many rich modeling constructs available in activity diagrams such as interruptible regions, activity groups, concurrent node executions, and flow final nodes. It is non-trivial to allow such constructs in IODs because their meaning has to be interpreted in the context of interaction sequences rather than activities. In this paper, we consider how some of these activity diagram constructs can be used practically in IODs. We motivate the integration of these constructs into IODs using a NASA air traffic control subsystem and define a formal semantics for these constructs that builds on an existing semantics definition for IODs.
- Activity diagrams
- Formal semantics